Electric switch



Nov. 12, 1940 R H SCHWTT 2,221,528

ELECTRIC SWITCH Filed May 17, 1938 `J4 da n Inventor: Richard H.Schmitt,

Patented Nov. l2, 1940 UNITED STATES PATENT OFFICE ELECTRIC SWITCH NewYork Application May 17, 1938, Serial No. 208,385

3 Claims.

This invention relates to electric switches, and more particularly toswitches of the quick make and break type.

It is an object of the invention to provide an improved constructionandy arrangement in switches of this type having a minimum of partswhich may be easily assembled within the switch casing. The constructionis reliable in operation and insures a rm and even contact between the lswitch circuit-closing members.

In the accompanying drawing, Fig. l is a sectional view through theswitch; Fig. 2 is a plan view of the bottom of the switch with theclosure cover removed; Fig. 3 is a perspective view of a l portion ofthe switch-operating mechanism; Fig. 4 is a view substantially along theline 4-4 of Fig. l with the switch housing in section; Fig. 5 is asectional view along the line 5-5 of Fig. l, and Fig. 6 is a perspectiveview of a portion of the switch mechanism showing one of the contacts inopen and in closed position.

Referring to the drawing, a housing I0, which may be formed ofinsulating material such as a phenolic condensation product and ller, or

the like, is provided for the switch mechanism.

-The housing is formed at the bottom with a substantially rectangularrecess Il for receiving the contact terminals of the switch mechanism,while a cavity I2 extends from the recess toward the top of the housingfor receiving the switch-operating handle. In order to provide formounting of the switch upon a base the housing is formed withdiametrically opposed openings I3.

According to the invention pairs of terminal members I4 and I5 arearranged symmetrically within the recess I I and are secured to thehousing by means of drive pins I6. Each of the terminal members isprovided with a terminal screw Il for connection to the conductors of anelecl, trical circuit. The conductors are led into the body of theswitch through the slots I8 which are disposed on opposite ends of theswitch housing and which merge with the recess I i. Each of the terminalmembers II is provided with a projecting contact I9, while the terminalmembers I5 are provided with similar contacts 2li.

In each case the contacts of each pair of terminal members cooperatewith a corresponding shorting roller or contact 2i mounted in a rocker22. The rocker 22 is formed of insulating material and is mounted in thevhousing by means of opposed bearing elements 23 disposed in grooves 22formed in the housing, the bearing portions being held in the grooves 24by means of a pin 25 extending through the housing. The pin 25 rests ingrooves 26 formed on each side of the housing so that the rocker 22 ispivotally mounted for oscillatory motion to and fro Within the housing.

The shorting rollers 2i are resiliently or mov- 5 ably mounted upon therocker 22 in order to make and break contact with the pairs of contactlugs I9 and 2li, respectively. To this end the shorting rollers aredisposed in grooves or slots 21 formed in the opposing arms 28 of therocker. The rolll0 ers are maintained in the grooves by the coiledtorsion springs 29 which are nested in slots 30 formed in each ofthearms 28. The U-shaped end 3I of the coiled torsion springs is disposedwithin the slot 30 and is retained therein by the 15 pin 32 integralwith the rocker, While the opposite prong ends 33 of 4the torsionsprings rest in grooves 34 formed on each of the ends of the shortingrollers and serve to maintain the rollers seated Within the slots 21.The torsion springs 20 29 maintain the shorting rollers securely seatedWithin the slots 2'I at all times.

Upon oscillating the rocker to switch-closing position the shortingrollers make contact with the contact lugs I9 and 20. At this time therocker continues to move to a position beyond that at which the rollersengage the contact lugs so that the rollers are retained against thecontact lugs and move a small distance Within the grooves 2l, as shownby Fig. 6. This relative movement between the rollers and rocker elementis permitted by exure of the torsion springs. The springs now aretensioned further to maintain the rollers rmly against the contact lugs.This construction ensures a rm contact between 1 the rollers and contactlugs under the inlluence of the'torsion springs and thus the contactpressure is not one which depends upon the degree of movement of therocker element upon operating the switch but depends upon the constantforce exerted by the torsion springs.

The rocker is provided with an operating handle 35 which projectsthrough an opening 36 formed in the top wall of the housing adjacent thecavity I2. Upon operation of the handle the switch may take either oftwo positions to close either the right or left-hand` pairs of contactsthrough the medium of the shorting rollers. In

.mid-position the switch is Oi.v The various positions of the rockerelement are determined i by a positioning mechanism comprising aplurality of grooves 31 formed integrally on each side of the body ofthe rocker element which cooperate with projections 39 formed in theside members 40 of a rectangular spring blade. The spring 40 comprises aflexure plate which is compressed between the positioning grooves 31 andthe top wall of the housing. Three of the grooves 31 are provided, thecenter one designating the OiI position and the two adjacent ones "Onpositions. As the switch is moved from one position to the other, thespring 40 is exed to permit the projections 39 to enter one of thegrooves 31.

The recess Il is closed by a plate 4| of insulating material providedwith a centrally disposed upstanding portion 42 which cooperates with arounded surface 43 on the rocker member to steady it in position. Theclosure plate is locked to the housing by means of a strap 44 havingbent-up ends 45 placed over the projections 46 formed on the outside ofthe housing.

In connecting up the switch the conductors are inserted through theslots or openings I8 and are connected to the terminal screws l1. As theswitch is operated to and fro the circuit across the pairs of contactlugs I9 and 20 is closed by means of the shorting rollers 2|. In somecircumstances, it may be desirable to interconnect two of the terminalmembers and such a connection is shown at 41. When the switch is turnedto circuit-closing position the snorting rollers are brought intocontact with the pairs of terminal contacts I9 and 20 and are iirmlyheld against them by the action of the torsion springs 29 which maintainexcellent electrical contact between the contacts and the rollers.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, a housing, spaced contacts mounted on opposite sidesof said housing. a rocker element pivotally mounted in said housing foroscillatory movement between said contacts, said rocker element having agroove and a slot therein, a shorting contact comprising a roller memberdisposed in said groove, spring means mounted in said slot on saidrocker element and having prong ends on each side of said elementengaging said contact to retain it within said groove, said spring meansbeing flexed upon engagement of said snorting contact with said spacedcontacts to permit relative movement between the rocker element andsnorting contact whereby said spring means maintains said shortingcontact in engagement with said spaced contacts.

2. In a switch structure, a housing having a recess therein, a rockerelement pivotally mounted within said recess and having opposed arms,each of said arms being provided with a groove and a slot therein, aroller contact element mounted in each of said grooves, spring meansmounted in each of said slots on said rocker element and each -havingprong ends disposed on opposite sides of said rocker element forengaging corresponding contact elements and retaining them within saidgrooves, pairs of contact members mounted in said recess and cooperatingwith each of said roller contacts, said roller contacts sliding in theirrespective grooves on engagement with said ilxed contacts underoscillatory vmovement of said rocker element and being held inengagement with said spaced contacts by the prong ends of said springmeans.

3. A switch comprising a housing, a rocker element mounted in saidhousing and having a groove and a slot therein, a roller contactslidably disposed in said groove, spring means mounted in said slot andhaving prong ends engaging said roller on each side of said rockerelement for retaining the contact within said groove, iixed contactsmounted in said housing and disposed on each side of said rocker elementfor engagement with said roller contact on oscillatory movement of saidrocker element, and a exible leaf spring engaging said rocker elementand the wall of said housing to position said rocker element in eithercontact closing or contact opening position.

RICHARD H. SCHMI'I'I.

